BTO - Breeding Birds of the Wider Countryside: Barn Owl

BARN OWL
Tyto alba

Barn Owl © Colin Varndell

Conservation listings

Europe: SPEC category 3 (declining)
UK: amber (25-50% distribution decline)

Long-term trend

UK: decline

Distribution maps

Maps and statistics from British and Irish
atlases can be viewed here.

Status summary

There is good evidence for a decline in this species that lasted throughout the 20th century, although there has been no annual monitoring until very recently. Productivity has tended to improve since the 1950s and 1960s when Barn Owls appear to have been affected by organochlorine pesticides (Percival 1990). Clutch sizes have risen, and nest failure rates have fallen at both the egg and nestling stages. A national census during 1995-97, organised jointly by Hawk & Owl Trust and BTO, has provided a replicable baseline estimate of c.4000 breeding pairs in the UK (Toms et al. 2001; for more information, click here). The lack of annual population change data for this species is now being addressed by the BTO's Barn Owl Monitoring Programme, which began in 2000; additional nest record, ringing and biometric information is also being collected through this scheme (Leech et al. 2003).

Annual breeding population changes for this species
are not currently monitored by BTO

Table of productivity information for Barn Owl

Variable Period
(yrs) Years Mean
annual
sample Trend Predicted
in first year Predicted
in last year Change Comment

Clutch size 34 1968-2002 13 Curvilinear 4.3 eggs 4.78 eggs 0.48 eggs Small sample

Brood size 34 1968-2002 69 Curvilinear 3 chicks 3.19 chicks 0.19 chicks

Daily failure rate (eggs) 34 1968-2002 11 Curvilinear 0.0042 nests/day 0.0004 nests/day -0.0038 nests/day Small sample

Daily failure rate (chicks) 34 1968-2002 41 Linear decline 0.0025 nests/day 0.0002 nests/day -0.0023 nests/day

Insufficient data on laying date
available for this species

Insufficient data on CES
available for this species


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This report should be cited as: Baillie, S.R., Marchant, J.H., Crick, H.Q.P., Noble, D.G., Balmer, D.E., Beaven, L.P., Coombes, R.H., Downie, I.S., Freeman, S.N., Joys, A.C., Leech, D.I., Raven, M.J., Robinson, R.A. and Thewlis, R.M. (2005) Breeding Birds in the Wider Countryside: their conservation status 2004. BTO Research Report No. 385. BTO, Thetford. (http://www.bto.org/birdtrends) Pages maintained by Susan Waghorn and Iain Downie: Last updated 18 January, 2006